1. Field of the Invention
This invention relates to a support device for medical instruments to be used for diagnosis, cure and medical treatment, and relates more particularly to support device for supporting operating instruments as spatulas and the like for cerebral microscopic operation and introducing them into fields or areas to be operated.
2. Description of the Prior Art
In cerebral surgical operation, it is generally required to reach an inner area to be operated securely, carefully displacing a brain of a patient with safety. For this purpose, spatulas have been used for long years. As the microscopic operation has become required fine operations in deeper areas, the fine adjustment and accurate holding of the spatulas in position, angle, direction and depth have been needed to a greater extent for the purpose.
The microscopic operation is generally accomplished by continuous and accumulated operations in small deep area to be operatd. In order to carry out the safe and secure operation, the path of spatula toward the target area must be narrow and as straight as possible to occupy the minimum space. The brain and structure adjacent thereto must be slightly and effectively displaced, preventing them from being wounded. Moreover the target in the deep area would be changed continuously or intermittently from a portion to another as the operation proceeds. Accordingly, various handling of the spatulas and the like for the operation must be effected with safety and security.
For this purpose, a brain protection and traction device is required to change or adjust finely its position, depth and direction and to be securely retained in position after every adjustments. In other words, the precise traction of the spatulas must be ensured in all angles, depths and positions.
The spatulas had been used being held by hand for operation and now they are often used in the same manner. However, the holding the spatula by hand is very unstable. In a fine operation in a deep area, it is quite impossible to hold a spatula unvarying without any slight movement for long hours.
In substitution for holding a spatula by hand, it has been suggested to provide a device including a rod-shaped or frame-shaped fixture onto which spatulas are fixed. However, it does not fulfil the requirements for the modern cerebral operation as follows.
The cerebral operation is not necessarily effected in a determined position and in a determined direction. It is required tomove spatulas finely and precisely and change them frequently immediately corresponding to the operations in all angles and directions. These movements of the spatulas must be effected by loosening and clamping the spatulas by hand out of the field of view of an operator by himself who is observing on the magnified tips of the spatulas and fields of the operation through an operating microscope. If the fine adjustments of the spatulas could not be freely carried out at desired time during the operation or securely holding them in the determined positions after the adjustments would not be stable, the microscopic operation will be greatly obstructed. Furthermore, the instruments and materials required for the operation must be located near the operator.
In order to fulfil these requirements, various devices have been investigated and developed, for example, Greenberg's "Universal Retractor", Sugita's "Cerebral Surgical Multipurpose Head Frame", Kanshepolsky's "Brain Retractor" and Yasargil's "Flexible Arm Type Retractor".
These devices all comprise spatula support rods which are elongated in roundabout way toward target areas to be operated. The roundabout path of the spatula support rod would obstruct the stability and accuracy in the fine positional adjustment and clamping of the spatulas. It has been found in practice that "fatigue phenomena" often occur in these device, which is a first problem to be solved.
The term "fatigue phenomenon" used herein means a phenomenon that a device exhibits an appearance as if it was senescent, resulting from increased clearances between relatively sliding parts due to wear. For example, members which should be horizontal are tilted due to increased clearance to exhibit a senescent appearance.
Although the Sugita's head frame is semicircular, it is only a single half annular frame having a narrow effective area and does not include a track for spatulas, so that the high freedom and fine adjustment could not be expected.
Greenberg's retractor includes tracks but is square configuration, so that sliding movements of spatulas are stopped at four corners to decrease the freedom and therefore roundabout rods are needed. The respective parts of the Greenberg's retractor are bulky which do not meet the fine adjustment of instruments required in the microscopic operation. This is very disadvantageous for delicate adjustments in cerebral microscopic operation.